Linum usitatissimum seed mucilage-alginate mucoadhesive microspheres of metformin HCl: Fabrication, characterization and evaluation

This study investigates the fabrication, characterization and optimization of Linum usitatissimum mucilage (LSM) with sodium alginate mucoadhesive microspheres loaded metformin HCl, a sustained release dosage form prepared by ionic gelation technique. The effect of changing the polymer ratio with drug was studied for drug encapsulation efficiency and in vitro drug release for 12 h. Drug entrapment efficiency of all formulations was in the range of 77.93 +/- 3.67 to 92.25 +/- 4.08% with sustained release of 80 +/- 0.12% to 88 +/- 0.33% for 12 h. It followed Korsmeyers Peppas model (R-2 = 0.9786-0.9964) with super case II transport mechanism. Average microsphere size of all formulations was within the range of 817-911 mu m. SEM, FTIR were also characterized and swelling behavior of microspheres was affected by pH of buffer medium. These microspheres also showed good mucoadhesivity in wash off test. The optimized LSM-alginate mucoadhesive microspheres containing metformin HCl demonstrated significant hypoglycemic effect in alloxan-induced diabetic rats for prolonged period of time. (C) 2020 Elsevier B.V. All rights reserved.